1. Field of the Invention
This invention relates to an information signal recording and/or reproducing apparatus, and more particularly, to a recording and/or reproducing apparatus performing a recording or reproducing operation on a tape-shaped record bearing medium wound around a pair of reels.
2. Description of the Prior Art
In conventional recording and/or reproducing devices such as video tape recorders, audio tape recorders, etc., information on the amount of tape used or remaining has been obtained by computing the amount of tape wound on one of the reels. Such computations have utilized the fact that the rotating speed of the supply reel or the take-up reel varies as the coil diameter of the tape or the reel varies. The computed information is displayed in various ways. Among the various known methods for carrying out such functions, some are simple arrangements compute the remaining amount of the tape on the supply reel by detecting the rotating speed of the supply reel and displaying the information.
In an apparatus arranged to obtain information concerning the remaining amount of tape, the detected tape computed can differ from the actual remaining tape because of variations or unevenness in the thickness of the tape and in the winding and tightening force exerted on the tape. In other words, the rotating speed varies because of these factors. Variations in the computed remaining amount of tape due to variations in the rotating speed and, therefore, the error, become larger as the coil diameter of the reel increases. These variations result in erroneous displays of the information on the remaining amount of tape. The displays sometimes indicate increasing amounts of tape while the actual amount of tapes remaining is gradually decreasing. This fosters mistrust and uncertainty in the mind of the operator. Further, where there is only a small amount of tape remaining, precise information on the remaining amount of tape is required. However, in such cases, the conventional display arrangement has failed to meet such precision requirements and caused great inconvenience and inaccuracy of measurement.